In grinding machines it is frequently desirable and necessary to condition or "dress" a grinding wheel surface at periodic intervals by means of passing a single point diamond dresser nib across a wheel surface. Dressing of the wheel cuts the matrix and fractures or tears out the dulled abrasive particles in the wheel face presenting fresh, sharp edges for continued cutting action.
The application of a single point diamond dresser nib to the wheel tends to create an area of high localized heat in the dressing zone, and overheating of the diamond tool may cause breakage or loss of diamond. The nib generally consists of a diamond embedded or bonded into a steel shank in the prior art. In order to cool the diamond to prevent overheating, the prior art devices teach that coolant fluid should be supplied on the wheel face so that there is a copious flow of coolant at all times around diamond contact at the wheel face, indicating that when this is not done, hot dry sparking of the diamond on the wheel, followed by plunging into the coolant may result in diamond breakage.
Some operations call for "dry grinding", especially where work must be visible during grinding. In these cases, dressing must also be done without coolant, and precautions must therefore be taken in allowing sufficient time to elapse between dressing passes in order to permit the diamond to cool.
One prior art diamond tool employs fins on the tool shank which extends from a housing to assist in cooling the tool. Another prior art device employs cross-drilled holes through the tool shank which extends from the tool holder with the expectation that an external coolant stream which impinges on the diamond contact point will be partially directed through the cross-drilled holes and assist in cooling. This latter prior art device tends to be much less effective when a dry grinding operation is performed than when wet grinding.
The within invention obviates the problems inherent in the prior art devices by design of a novel diamond dresser unit which purposefully conducts heat from a dressing zone through the diamond and diamond nib shank to an internal cavity in the dresser nib holder, where a closed circuit coolant fluid is circulated to efficiently carry away heat when either a dry or wet grinding operation is being performed.
It is therefore an object of the present invention to provide a grinding wheel dresser unit having improved heat transfer capabilities.
It is another object of the present invention to provide a heat-conducting wheel dresser system which may be effectively used when either dry or wet grinding operations are performed.